Keyhole guard



Sept. 25

W. D. BRESEE KEYHOLE GUARD Original Filed 001:. l. 1921 :iil Kril ail-L Patented Sept. 25, 1 923.

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KEYHQLE GUARD.

Application filed October 1, 1321, e rial Ho. 504,580. Renewed my 5, 323."

T all whomit may concern: 7

Be it known that L'lVnrc-rrr l). Bnnsnn, a citizen of the United States, residing at Los Angeles. in the county of Los' Angeles.

and State of California, have inventednew and useful Improvements in Keyhole Guards, of which the following 15 a specification.

My invention relates to a devicetor closing a key hole against the insertion ofa key or 0t er article. 7

An object of my invention is to provide a guard for key holes adapted to be int a duced into a key hole and engaged v itli the walls thereof in such manner as to inhibit insertion of a key or other device and thereby effectively prevent tamperingwith the lock.

-Another object is to provide a device of; the above character which is adaptedto be locked in engagement :with the key hole walls by a key controlled mechanism in such fashion as to effectively hold it place against unauthorized removal.

A further object is to provide akey hole guard of the above type which is adapted to be employed in key holes of various sizes.

Other objects will appear hereinafter.

The invention is illustrated in the accompanying drawings, in which V Figure l is a view of a lock as seen in transverse vertical section through the key hole, showing the manner of applying the guard and illustrating it in its open and locked position; 7

Figure 2 is a view of the guard as seen in side elevation, showing it in its closed posi tion.

Figure 3 is a view of the guard as seen in longitudinal vertical section with parts in elevation. V

Figure t is a rear end View.

Figure 5 is a front end view.

Figure 6 is a view in section as seen on the line 6-6 of Figure 3.

In carrying out my invention, I employ a tubular casing 7 preferably formed of cast metal and having its interior providedwith two concentric cylindrical chambers of different diameters; the smaller chamber 8 opening at the outer end of the casing and the larger chamber 9 opening at the inner end thereof. lhe bottom wall of the casing is formed throughout with a longitudinal slot or channel 10 which opens to the cham- .ber 9 and mounted in this channel is a sheet metal housing '11 comprising parallel side walls ab, a bottom wall 'aand an endwalk (Z,- the housing being inserted in the channel and brazed to the casin with theend wall d extending ad acent the outer end of the casing and its open end projecting short distance forwardv of theinner' end'ot the pivotally mounted 'inthe housing by a pin 13 and pro ects'through the open end of the housing, and -11101111tGCl in the housingis a spring 1s adapted to normally-retain the arm in an uppermost position. The outer teeth 15.

Revolvabiy mounted in the chamber. 8 is a tubular cylinder 16 formed with a lon-gi tudinal slot 17 ;'the outer end of the cylinder end portion of the arm is formed on its= Lower edge with aseries of serrations or chamber 9, which disk constitutes a cam adapted on rotation of the) cylinder to act on the arm"12 and against which the arm, bearslunderpressure oi the spring 1 1.

The inner end of the casing is ClOSGClby a plate 23' which seats against the end face 01 the dlsk 22 and is held in place by an inturned flange or bead 24 on the end of the casing; the plate being termed withaslot 25 with which the side walls of the housing eter slightly less than the circular portion of are engaged to hold the plate against turn ung. fiigidly mounted on the end plate and ordinary key hole. The upper face of the stem is formed with a series of shallow serraplates within alock. r

In the operationof the invention the cylinder 16 is positioned to dispose the cam disk 5 22 with its overhangingportion clear oi the locking arm, so that the latter will be retracted by the spring and held close to the stem substantially in alignment therewith, as:

shown in Figures 3 and i. The stem and arm are then inserted in a :key hole with the stem arranged in the upper circular portion of the hole and the arm arranged within the depending slot portion of the hole. The cylinder 16 is then turned by the key QOIO-CZHLSG the cam disk to turn and move the arm 12 downwardly on its pivot and bring the teeth 15 into engagement with the lower edges of the key hole in the plates within the lock and at the same time cause thestein to bear upwardly into engagement with the upper edges of the keyhole openings, as shown in Figure 1. The cam disk will then serve to maintain the a rln'in an open position within the key hole and the serrations ot the arm and the stem will hold the device against being disengaged it'rom the lock until the cam and arm are again retracted. lVhen'the device is thus secured in place in the key hole the latter will be effectively blocked against the insertion of a key or other implement, so that the lock will be protected against picking or tampering;

It will now be seen that I- have provided a simple device for carrying out the objects set forth, but while I have described the inven-v tion specifically I do not desire to limit myself to the exact details of construction shown, but may employ such changes in the fixed stem on said casing adapted to be inserted 1n the upper portion of .a. key hole, a housing on sald caslng, an arm pivoted in said honsing extending beneath said stem in said arm in opposition to said spring and position the arm in spread relation to said stem.

2. A keyhole guard comprising a casing a fixed stem on said casing adapted to be inserted in the upper portion of a key hole, a housing on said casing, an arm pivoted in said housing extending beneath said stem in alignment therewith and adapted to be inserted in the lower portion of a key hole, a spring normally maintaining said arm in a retracted position, a cylinder rotatable in said casing having a key receiving slot, and a cam a'lfixed on said cylinder to turn therewith arranged to bear on said arm and adapted on rotation of said cylinder to depress said arm in opposition to said spring and position the arm in spread relation to said stem; said stem and arm being formed with serrations adapted to he engaged with the upper and lower margins of key hole openings within a lock.

WRIGHT D. BRESEE. 

